Dell Inspiron 660 Graphics Card & PSU compatible/will fit?

First off: Never, ever buy a cheap power supply. You're just begging for fried components and fireworks if you do. I know this from first hand experience.

Second: The 650 Ti is a great card, but if you're just getting a reference card go for the 750 Ti. Lower power consumption and better performance.

For power supplies, I'm not the best to talk to. However, after recommendations from experts here, I eventually decided on this power supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817371056

Which is a bit too much for what you plan on getting, but I'm just trying to put it into perspective. I'm sure a PSU expert will pop up here, they know what they're talking about :)

Good luck!